Keeping frog disease under control

A workshop on new methods of detecting and controlling the spread of one of the world's most deadly frog diseases " chytridiomycosis " was recently held at CSIRO Livestock Industries' Australian Animal Health Laboratory (AAHL) in Geelong, Victoria.

CSIRO Livestock Industries' Dr Alex Hyatt says the disease, caused by the chytrid fungus, has been associated with frog declines in eastern Australia, New Zealand, the United States, Panama, Ecuador, Venezuela and Spain.

"At least one Australian frog species has been wiped out by the chytrid fungus and it is thought that the fungus was a major contributing factor in the extinction of at least another seven species worldwide," Dr Hyatt says.

"In response to this major threat, AAHL has developed diagnostic assays and sampling techniques that enable the rapid detection of the fungus.

"We've developed immunohistochemical, molecular and electron microscopy tests for the fungus, along with a range of sampling assays. Using wash water or swabs, tadpoles and frogs can be tested for infection, with the sampling assays detecting even low levels of fungus zoospores," Dr Hyatt says.

Many of the workshop sessions will be held within the microbiologically secure section of AAHL, where biosecurity is stringent. Not only must the participants take a compulsory shower before leaving the high-biocontainment facility, but they will not be allowed to be in contact with livestock and amphibians for seven days after completing the workshop.

Dr Hyatt says an important reason for holding the workshop is to attempt to standardise the diagnostic procedures used throughout the world.

"If labs worldwide are using standardised assays in the same way then we can realistically compare data and work together to develop effective management programs.

"The challenge is to determine where the fungus is in the environment and which species are susceptible. Once we know that, we can implement procedures to protect animals and the environment," Dr Hyatt says.

The workshop's presenters included: Dr Joyce Longcore from the University of Maine, Associate Professor Rick Speare and Dr Lee Berger from James Cook University and Dr Hyatt.